<template>
    <div class="cmt-container"> 
        <h3>发表评论</h3>
        <hr>
        <textarea placeholder="请输入要评论的内容（120字以内）"
         maxlength="120" v-model="msg"></textarea>

         <mt-button type="primary" size="large" @click="postComment()">发表评论</mt-button>

        <div class="cmt-list">
            <div class="cmt-item" v-for="(item, i) in comments" :key="item.add_time">
                <div class="cmt-title">
                    第 {{ i+1 }}楼&nbsp;&nbsp;用户：{{ item.user_name }}&nbsp;&nbsp;发表时间：{{ item.add_time | dateFormat }}
                </div>
                <div class="cmt-body">
                    {{ item.content }}
                </div>
            </div>
        </div>

        <mt-button type="danger" size="large" plain @click="getMore()">加载更多</mt-button>

    </div>
</template>

<style scoped>
.cmt-container h3{
    font-size: 18px;
}

textarea{
    font-size:14px;
    height: 85px;
    margin: 0;
}

.cmt-list{
    margin: 5px 0;
    
}

.cmt-list .cmt-item{
    font-size: 13px;
}

.cmt-list .cmt-item .cmt-title{
    background-color: #ccc;
    line-height: 30px;
}

.cmt-list .cmt-item .cmt-body{
    line-height: 35px;
    text-indent: 2em;
}
</style>

<script>
import { Toast } from "mint-ui"

export default {
    data() {
        return {
            pageIndex: 1, //默认展示第一页数据
            comments: [], //所有的评论数据
            msg: '' //评论输入的内容
        }
    },
    created(){
        this.getComments()
    },
    methods: {
        getComments(){
            this.$http.get("api/getcomments/"+this.id+"?pageindex=" +this.pageIndex)
                .then(result => {
                    if(result.body.status === 0){
                        // this.comments = result.body.message;
                        //数组拼接，这样就不会覆盖掉第一页的数据
                        this.comments = this.comments.concat(result.body.message)
                    }else{
                        Toast('获取评论数据失败')
                    }
                })
        },
        getMore(){//加载更多
            this.pageIndex ++;
             this.getComments();
        },
        postComment(){//发表评论
            //校验是否为空
            if (this.msg.trim().length === 0){
                return Toast("评论内容不能为空！");
            }

            //发表评论：
            //参数1：请求的 URL 地址
            //参数2：提交给服务器的数据对象 { content: this.msg }
            //参数3: 定义提交时候，表单中数据的格式 { emulateJSON:true }
            this.$http.post('api/postcomment/' + this.$route.params.id, 
            {content: this.msg.trim()})
            .then( result => {
                if(result.body.status ===0 ){
                    //1、拼接出一个评论对象
                    var cmt = {
                        user_name: '匿名用户',
                        add_time: Date.now(),
                        content: this.msg.trim()
                    };
                    this.comments.unshift(cmt);
                    this.msg = "";
                }
            });
        }
    },
    props: ["id"]
}
</script>